What is the greatest single Agronomic Practices for ... · Agronomic Practices for Irrigated Corn v20121210 © Purdue Univ. 1 v20121210 © Purdue Univ. 1 Agronomic Practices for Irrigated

Agronomic Practices for Irrigated Corn v20121210

© Purdue Univ. 1

v20121210 © Purdue Univ. 1

Agronomic Practices for Agronomic Practices for Irrigated Corn ProductionIrrigated Corn Production

R.L. (Bob) NielsenR.L. (Bob) Nielsen

Purdue University AgronomyPurdue University Agronomy

Email: Email: [email protected]@purdue.edu

KingCornKingCorn:: www.kingcorn.orgwww.kingcorn.org

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What is the greatest single What is the greatest single obstacle to consistently obstacle to consistently achieving higher corn yields?achieving higher corn yields?


““NormalNormal”” growing seasons!growing seasons!

“Normal” growing seasons are those that involve an unpredictable number of unpredictable extreme weather events, each occurring unpredictably, with unpredictable severity.

The frequency of The frequency of extreme weather events extreme weather events is becoming is becoming more prevalent.more prevalent.

Image source: http://www.keepbanderabeautiful.org/climate-change.jpg


Consequently, our greatest Consequently, our greatest agronomic challenge today is to agronomic challenge today is to stressstress--proof our proof our crops against crops against unpredictable, unpredictable, extreme extreme weather events.weather events.


Bad news & Good newsBad news & Good news

The effects of weather stress on crop growth and yield are compounded by the presence of other yield-limiting factors. Soil compaction, nutrient deficiencies, disease

damage, insect injury, weed competition, poorly drained soils, or any of the other gazillion yield-limiting factors that influence crop growth & yield.

That’s the bad news.


Also good news becauseAlso good news because……

If you can identify and manage other yield-limiting factors, this will help you “stress-proof” your cropping system against the vagaries of Mother Nature.

Image source: http://typesofpoetry99.blogspot.com/2010/01/mother-nature.html


© Purdue Univ. 2


Yield influencing factors (YIFs)Yield influencing factors (YIFs)

Can be positive or negative. Pay attention to both.

Some occur every year.........some do not.

Often interact with each other.

Often influence different crops differently.

Almost always interact with the weather.


How to identify YIFs?How to identify YIFs? Spend time with your crops.

Educate yourself.

Consult folks w/ experience.

Document everything.

Spend time with your crops.

Attention to detail.

Identify problems early.

Diagnose every problem.

Spend time with your crops.


Optimum grain yield develops Optimum grain yield develops throughout the entire growing season.throughout the entire growing season.

Source of graphic: NielsenSource of graphic: Nielsen’’s imaginations imagination


Optimum grain yield begins withOptimum grain yield begins with……

Establishing a healthy, vigorous stand of corn by the time the crop has reached about V6 (knee-high). Choice or luck with planting dates.

Seedbed & initial growing conditions.

Speed & uniformity of germination / emergence.

Initial population vs. seeding rate.

Success of initial root development.

Image: RLNielsen


Optimum yield continues withOptimum yield continues with……

Maintaining the health of the root system and crop canopy throughout the entire growing season. Soil fertility / plant nutrition

Plant health (diseases)

Plant health (insects)

Soil tilth, health, quality factors

Image: RLNielsen


How to raise the How to raise the ““yield baryield bar”…”…

I do not have all the answers.

But, then, neither does anyone else.

Let me share with you some of the key factors that I believe to be important for raising the “yield bar” for corn in the eastern Corn Belt. Maybe some of these agronomic factors will

resonate with you also.


© Purdue Univ. 3


Common thread of first 3 factors:Common thread of first 3 factors:

Water… Too much

Not enough

Seasonal rainfall distribution

Soil water-holding capacity

Water infiltration vs. runoff

Image source: Image source: http://typesofpoetry99.blogspot.com/Image source: Image source: http://typesofpoetry99.blogspot.com/2010/01/mother2010/01/mother--nature.htmlnature.html


Soil drainageSoil drainage……

Improve drainage (tile, surface) in naturally poorly-drained soils. Reduces risk of ponding and saturated soils.

Reduces risk of soil N loss.

Reduces risk of soil compaction from tillage, planter, & other equipment.

Reduces risk of cloddy seedbeds from tillage.

Enables successful root development and stand establishment of the crop.

Image Image ©© Purdue Purdue UnivUniv; ; RLNielsenRLNielsen


Moisture conservationMoisture conservation……

And soil erosion control (water, wind) on rolling topography or sandy soils. No-till or reduced tillage

Contour farming and/or strip cropping

Terraces & other water control structures

Fall / winter cover crops

All help maximize soil moisture availability later in the season.

Image source: http://media.web.britannica.com/ebImage source: http://media.web.britannica.com/eb--media/99/65699media/99/65699--050050--B9FC6122.jpgB9FC6122.jpg


IrrigationIrrigation……

Supplement rainfall w/ irrigation Above-ground irrigation (row, pivots, etc.)

Sub-irrigation via back-filling of tile drains or drainage ditches.

Requires informed decision-making relative to irrigation scheduling.

Requires optimum maintenance & proper operation of irrigation systems.

Image: http://www.prlog.org/11281609-watering-can.jpg


Daily Yield Loss Due to Severe Drought Stress

0

1

2

3

4

5

6

7

8

9

12- to 16-leaf 16-leaf totassel

Pollination Blister Milk Dough Dent Maturity

Yie

ld lo

ss p

er d

ay o

f st

ress

(%

)

Max

Avg

Min

Adapted from Fig. 11; Shaw, Robert. 1977. “Climatic Requirement”, Ch. 10 in Corn & Corn Improvement, ASA Monograph No. 18

These estimates are applicable for situations where drought stress occurs for “a few days”.


Pollination: Synchrony & viability

Synchrony between silk emergence & pollen shed

Viability of exposed silks & airborne pollen

Adequate Ps rates to avoid kernel abortion

Adequate Ps rates to maximize kernel weight


© Purdue Univ. 4


EvapoEvapo--transpiration (ET) by corntranspiration (ET) by corn

Early in the season, ET is primarily driven by soil moisture evaporation.

As plants develop, ET is driven primarily by transpiration by the plants, but declines as plants mature during grain fill.

Thus, seasonal ET for a corn crop looks like a typical “bell” curve…


Seasonal water use by cornSeasonal water use by corn

Graphic source: Irrigation Management for Corn. Univ of Nebr Extension pub G1850. http://www.ianrpubs.unl.edu/epublic/live/g1850/build/g1850.pdf

Smooth curve “A” = Long-term seasonal water use per day

Variable curve “B” = Potential variability for water use per day


Water requirements for cornWater requirements for corn

From 20 to 25 inches total (soil reserves + rainfall + irrigation). For you trivia fans, an acre-inch of water

equals 27,154 gallons; so an acre of corn requires as much as 678,850 gallons of water in a growing season. Depending on soil texture

and depth, soil moisture capacity may be as great as 10 to 12 inches.


Maximum water holding capacity Maximum water holding capacity among soil texture classesamong soil texture classes

0.0

0.5

1.0

1.5

2.0

2.5

3.0

Soil texture

Inch

es p

er f

oo

t o

f so

il

Coarse sand

Fine sand

Loamy sand

Sandy loam

Fine sandy loam

Silt loam

Silty clay loam

Silty clay

Clay

Source: Physical Properties of Soil and Soil Water. Univ of Nebraska; Plant & Soil Sciences eLibrary. http://passel.unl.edu/pages/printinformationmodule.php?idinformationmodule=1130447039


Improved irrigation managementImproved irrigation management

Make more informed decisions on when to irrigate and how much water to apply. Capacity of irrigation water supplyWell, reservoir, river, drainage ditchPump capacity (gal/min)

Efficiency (accuracy) of irrigation system Soil water holding capacity & current status Water needs (ET) of the crop Anticipated rainfall


http://www.ianrpubs.unl.edu/epublic/live/g1850/build/g1850.pdf

Also, this one from Michigan State Univ:

http://msue.anr.msu.edu/news/drought_irrigation_management


© Purdue Univ. 5


Hybrid selectionHybrid selection

There is a lot of money to be made or lost with this one decision. As much or more than any other crop input

decision corn growers make every year.

Just look at the bushel differences between the highest to lowest yielding hybrids in any public variety trial. Assuming companies do not enter crappy™

hybrids in variety trials!


Bushel difference Bushel difference –– hi hi vsvs lowlow

68 71 68

56

79

49

95

50

131

23

N1 N2 N3 N4 C1 C2 C3 S1 S2 S3Indiana Location

Purdue Univ. Corn Performance Trials 2010 Late Relative Maturity Results

Data source:Data source:http://http://www.ag.purdue.edu/agry/PCPP/Pages/corn.aspxwww.ag.purdue.edu/agry/PCPP/Pages/corn.aspx

Let’s see… With $7 corn… A lot of money!


Yield potential AND consistencyYield potential AND consistency

In the absence of stress, hybrids yield differently simply due to differences in genetic yield potential.

CONSISTENCYCONSISTENCY of yield performance over years and across locations is based on how well hybrids tolerate unforeseen and unpredictable stresses.


So, your challenge is toSo, your challenge is to……

Identify hybrids that tolerate a wide range of growing conditions. Evaluate variety trial results from a lot of

locations (i.e., growing conditions) and look for hybrids whose yields are at least 90% that of the highest yielding hybrid in almost every variety trial you can find.

Do not relegate this decision solely to your seed dealer. Be a participant in the process!


Drought tolerant hybrids?Drought tolerant hybrids?

There is no single common trait among hybrids currently labeled “drought tolerant” Simply have shown the ability to yield better

than others under water-limited conditions.

If you can find the evidence that supports their superiority for yield and consistency of yield across a wide range of growing conditions, go for it.


Drought Drought ““tolerancetolerance”” vs. vs. ““resistanceresistance””

It is important to recognize that these hybrids are not RESISTANT to drought.

In other words, the current drought tolerant hybrids still need water to produce grain. They will suffer under drought; but not, apparently, as much as other hybrids.

© 2005 Purdue Univ; RLNielsen


© Purdue Univ. 6


Drought Drought ““tolerancetolerance””; not ; not ““resistanceresistance””

E.g., Pioneer AQUAmax™ 2012 reports*: Across 3,606 water-limited environments, out-

yielded “competitive” hybrids 69% of the time by an average of 8.9% or about 8.5 bu/ac.

Let’s do the math: 8.5 bu = 8.9% better than competitorsTherefore, competitors’ avg yield = ??

• Competitors’ avg yld = 8.5 divided by 0.089 = 95.5 bu/ac

• So, the avg AQUAmax yield was 95.5 + 8.5 = 104 bu/ac

* Online at https://www.pioneer.com/home/site/us/products/corn/seed-traits-technologies/yield-data-early-look


Soil Soil tilthtilth, , ““healthhealth””, or , or ““qualityquality””

Minimize the risk of soil compaction caused by tillage or other equipment.

Minimize tillage traffic or adopt outright no-till where appropriate.

Minimize grain cart traffic and other heavy equipment on your fields.

Include fall or winter cover crops where appropriate.


Crop rotationCrop rotation……

Avoid continuous corn, especially no-till corn after corn… Too many challenges. Surface corn stover delays soil drying /

warming and can interfere with planter operation.

Decomposing corn stover immobilizes soil N.

Corn stover harbors disease inoculum.

Continuous cropping puts “all the eggs into one basket” in terms of weather stresses.


Relative Crop Yield Loss2012 Indiana

Corn-38.1%

Soybean-9.3%

Wheat-6.60%

-45%

-40%

-35%

-30%

-25%

-20%

-15%

-10%

-5%

0%

Per

cen

t d

epar

ture

fro

m t

ren

d

Timing of weather stress dictates which crop suffers less, but not always predictable.


Starter fertilizerStarter fertilizer……

Adopt a robust 2x2 starter fertilizer program; especially in terms of starter N. In challenging conditions, starter N aids young

corn plants (V3 – V5) as they “wean”themselves from the kernel reserves to dependence on nodal roots.

Consider starter N rates no less than 30 lbs actual N /ac, and maybe higher for no-till continuous corn or corn into cover crops.


Nitrogen managementNitrogen management……

Implement nitrogen management practices that minimize risk of N loss and maximize N use efficiency by the corn crop. Avoid fall N applications (risk of N loss).

Avoid early spring N applications (N loss)

Avoid surface-applied urea-based fertilizers without incorporation (risk of N loss).

Sidedress or split-apply N where practical.


© Purdue Univ. 7


Risk of N loss with irrigationRisk of N loss with irrigation……

Is inherently greater than many rain-fed situations elsewhere, primarily because of sandier soils that cannot “hang on” to nitrate-nitrogen.

Thus, greater value to… Sidedressing or fertigation

Ammonia vs. UAN; especially pre-plant

Nitrification or urease inhibitors; esp. pre-plant


Thoughts on N fertilizer ratesThoughts on N fertilizer rates

Optimum N fertilizer rate is not correlated with yield potential! Corn generally requires about 275 TOTAL lbs

of actual N per acre (soil + fertilizer).

Rotation corn N guidelines (lbs of actual N applied per acre) Low risk of N loss: 180 – 190 lbs High risk of N loss: 210 – 220 lbs

Continuous corn about 40 lbs higher

Based on nearly 200 field-scale research trials conducted since 2006


Yield Response to Applied NIrrigated Loamy Sand, fine Sandy Loam

0

50

100

150

200

250

50 100 150 200 250 300

Total applied N (lbs actual N / ac)

Gra

in y

ield

(b

u /

ac

)

Max. yield @ 225 lbs N / ac

Northcentral (2, corn/corn) & northeast (1, corn/soy) Indiana

By comparison, average opt. N rate in 9 non-irrig. sandy trials = 203 lbs N / ac


WeWe’’re looking for collaboratorsre looking for collaborators……

To participate in on-farm trials evaluating N fertilizer rates under irrigated and non-irrigation conditions.

Variable rate, Rx-driven controller simplifies logistics.

Auto-steer may be beneficial.

GPS-enabled grain yield monitor simplifies harvest.


OnOn--farm corn N rate trialsfarm corn N rate trials

Typically, five to six N rates. Range of rates negotiable, but low to high

Replicated 3 to 6 times. Field length plots, ~ twice combine width

Option to include seeding rates.

Option to include 2 hybrids (split-planter).


Disease managementDisease management……

Yield losses from foliar diseases can easily lower corn yields by 20% or more.

Implement sound disease management strategies that include… Hybrid selection for disease resistance

Crop rotation

Tillage (where appropriate)

Foliar fungicides (if needed).


© Purdue Univ. 8


Surface Surface ““trashtrash”” in noin no--tilltill……

Manage surface “trash” in no-till to hasten drying / warming of soil, facilitate effective planter operation, and improve crop emergence & stand establishment. Kill winter annual weeds and / or cover crops

before their growth becomes unmanageable. Use row-cleaners on the planter row units. Minimize the risk of furrow sidewall or surface

compaction by avoiding planting when soil moisture is “on the wet side”.


Seeding RatesSeeding Rates


Balancing act for cornBalancing act for corn……

More plants per unit area equals more ears per unit area. (that’s good)

But, ear size per plant decreases with increasing plant density. (that’s not good)

The optimum final stand is that which best balances the decrease in ear size per plant with the gain in ears per unit area.

Furthermore, stalk health & integrity at higher populations sometimes falters.

Image: http://ascannerdorky.files.wordpress.com/2007/07/balancing-act-001.jpg

Seeding Rates


General observationsGeneral observations

Little difference for optimum harvest population at yield levels ranging from low 100’s to low 200’s.

Few differences between well-rainfed and irrigated corn.

Few differences among hybrids.

Little evidence that higher seeding rates require more N fertilizer.


Average Harvest Populations Over TimeIndiana (all) vs. Nebraska (irrig)

29,750

29,000

10,000

15,000

20,000

25,000

30,000

35,000

1995 2000 2005 2010 2015

Ha

rve

st

pla

nt

po

pu

lati

on

(p

lts

/ac

)

IN - All

NE - irrig

Little to no difference in plant populations between (mostly) rainfed Indiana and irrigated Nebraska corn

Data: USDA-NASS


OnOn--farm corn seeding rate trialsfarm corn seeding rate trials

Since 2010, I have been involved with 27 field-scale or on-farm seeding rate trials around the state. Other field-scale trials back in the early 2000’s

bring the total number up to 37 trials.


© Purdue Univ. 9


Corn Yield Response to Plant Population36 Field-Scale Trials, Indiana, 2001 - 2012

0%

20%

40%

60%

80%

100%

120%

18,000 23,000 28,000 33,000 38,000 43,000 48,000

Plant population (plts/ac)

Pe

rce

nt

of

ma

xim

um

yie

ld

RLNielsen, Purdue Univ.

Avg. max. yield responseamong 36 trials = 28,375 plts/ac @ 95% stand ~ 30,000 seeds/ac

Opt. population for 9 trials in 2012 no different than previous 27 trials


Agronomic Optimum plant population vs. Optimum Yield

36 Field-Scale Trials, 2001 - 2012

-

5,000

10,000

15,000

20,000

25,000

30,000

35,000

40,000

45,000

80 100 120 140 160 180 200 220 240

Yield at optimum plant population

Op

tim

um

pla

nt

po

pu

lati

on

2011-2011

2012

RLNielsen, Purdue Univ.

Optimum plant population is not strongly Optimum plant population is not strongly dependent on productivity (yield) leveldependent on productivity (yield) level……

What does this suggest for variable rate What does this suggest for variable rate seeding?seeding?

95% of the trials had optimum plant 95% of the trials had optimum plant populations between 24 and 33,000 populations between 24 and 33,000 pltsplts/ac/ac


Variable seeding ratesVariable seeding rates……

In all honesty, there is probably a maximum of two meaningful seeding rates that might be used in any given field…. A rate on the lower end for challenging soils.

Approximately 130 bpa or lower.

Seeding rates ~ 25,000 spa

A rate on the higher end for everything else.

Seeding rates ~ 32,000 spa

Image and opinion: Image and opinion: RLNielsenRLNielsen


WeWe’’re looking for collaboratorsre looking for collaborators……

To participate in on-farm trials evaluating seeding rates under irrigated and non-irrigated conditions.

Variable rate, Rx-driven controller simplifies logistics.

Auto-steer can be beneficial.

GPS-enabled grain yield monitor simplifies harvest.


OnOn--farm corn seeding rate trialsfarm corn seeding rate trials

Typically, five to six seeding rates. Range of rates negotiable, but ~25 to 45k

Replicated 3 to 6 times. Field length plots, ~ twice combine width

Option to include nitrogen rates.

Option to include 2 hybrids (split-planter).


Remember, it Remember, it ainain’’tt rocket science!rocket science!

The key factor is to identify those yield limiting factors that are most important for your specific farming operation.

Together with your crop advisor(s), identify & implement good agronomic management practices to target those yield limiting factors.

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What is the greatest single Agronomic Practices for ... · Agronomic Practices for Irrigated Corn v20121210 © Purdue Univ. 1 v20121210 © Purdue Univ. 1 Agronomic Practices for Irrigated